/**
 * Copyright (C) 2002-2015   The FreeCol Team
 * <p>
 * This file is part of FreeCol.
 * <p>
 * FreeCol is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 * <p>
 * FreeCol is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * <p>
 * You should have received a copy of the GNU General Public License
 * along with FreeCol.  If not, see <http://www.gnu.org/licenses/>.
 */

package net.sf.freecol.common.networking;

import net.sf.freecol.common.model.Game;
import net.sf.freecol.common.model.Player;
import net.sf.freecol.common.model.Region;
import net.sf.freecol.common.model.Tile;
import net.sf.freecol.common.model.Unit;
import net.sf.freecol.server.FreeColServer;
import net.sf.freecol.server.model.ServerPlayer;

import org.w3c.dom.Element;


/**
 * The message sent when naming a new region.
 */
public class NewRegionNameMessage extends DOMMessage
{

    /** The object identifier of the region being discovered. */
    private final String regionId;

    /** The tile where the region is discovered. */
    private final String tileId;

    /** The unit making the discovery. */
    private final String unitId;

    /** The new name. */
    private final String newRegionName;


    /**
     * Create a new <code>NewRegionNameMessage</code> with the
     * supplied name.
     *
     * @param region The <code>Region</code> being discovered.
     * @param tile The <code>Tile</code> where the region is discovered.
     * @param unit The <code>Unit</code> that discovers the region.
     * @param newRegionName The default new region name.
     */
    public NewRegionNameMessage( Region region, Tile tile, Unit unit,
                                 String newRegionName )
    {
        super( getXMLElementTagName( ) );

        this.regionId = region.getId( );
        this.tileId = tile.getId( );
        this.unitId = unit.getId( );
        this.newRegionName = newRegionName;
    }

    /**
     * Create a new <code>NewRegionNameMessage</code> from a
     * supplied element.
     *
     * @param game The <code>Game</code> this message belongs to.
     * @param element The <code>Element</code> to use to create the message.
     */
    public NewRegionNameMessage( Game game, Element element )
    {
        super( getXMLElementTagName( ) );

        this.regionId = element.getAttribute( "region" );
        this.tileId = element.getAttribute( "tile" );
        this.unitId = element.getAttribute( "unit" );
        this.newRegionName = element.getAttribute( "newRegionName" );
    }


    // Public interface

    /**
     * Public accessor for the region.
     *
     * @param game The <code>Game</code> to look for a region in.
     * @return The region of this message.
     */
    public Region getRegion( Game game )
    {
        return game.getFreeColGameObject( regionId, Region.class );
    }

    /**
     * Public accessor for the tile.
     *
     * @param game The <code>Game</code> to look for a tile in.
     * @return The tile of this message.
     */
    public Tile getTile( Game game )
    {
        return game.getFreeColGameObject( tileId, Tile.class );
    }

    /**
     * Public accessor for the unit.
     *
     * @param player The <code>Player</code> who owns the unit.
     * @return The <code>Unit</code> of this message.
     */
    public Unit getUnit( Player player )
    {
        return player.getOurFreeColGameObject( unitId, Unit.class );
    }

    /**
     * Public accessor for the new region name.
     *
     * @return The new region name of this message.
     */
    public String getNewRegionName( )
    {
        return newRegionName;
    }

    /**
     * Handle a "newRegionName"-message.
     *
     * @param server The <code>FreeColServer</code> handling the message.
     * @param player The <code>Player</code> the message applies to.
     * @param connection The <code>Connection</code> message was received on.
     *
     * @return Null.
     */
    public Element handle( FreeColServer server, Player player,
                           Connection connection )
    {
        final ServerPlayer serverPlayer = server.getPlayer( connection );
        final Game game = server.getGame( );

        Tile tile = getTile( game );
        if ( ! serverPlayer.hasExplored( tile ) )
        {
            return DOMMessage.clientError( "Can not claim discovery in unexplored tile: " + tileId );
        }

        Unit unit;
        try
        {
            unit = getUnit( player );
        }
        catch ( Exception e )
        {
            return DOMMessage.clientError( e.getMessage( ) );
        }

        Region region = tile.getDiscoverableRegion( );
        if ( region == null )
        {
            return DOMMessage.clientError( "No discoverable region in: "
                                                   + tileId );
        }
        if ( ! region.getId( ).equals( regionId ) )
        {
            return DOMMessage.clientError( "Region mismatch, " + region.getId( )
                                                   + " != " + regionId );
        }

        // Do the discovery
        return server.getInGameController( )
                .setNewRegionName( serverPlayer, unit, region, newRegionName );
    }

    /**
     * Convert this NewRegionNameMessage to XML.
     *
     * @return The XML representation of this message.
     */
    @Override
    public Element toXMLElement( )
    {
        return createMessage( getXMLElementTagName( ),
                              "region", regionId,
                              "tile", tileId,
                              "unit", unitId,
                              "newRegionName", newRegionName );
    }

    /**
     * The tag name of the root element representing this object.
     *
     * @return "newRegionName".
     */
    public static String getXMLElementTagName( )
    {
        return "newRegionName";
    }
}
